STS091-707-012 (2-12 June 1998) --- This nearly vertical photograph of Houston was taken from the Space Shuttle Discovery. Houston is an inland port city, linked by the Houston Ship Channel to the Gulf of Mexico and the Intracoastal Waterway at Galveston, 51 miles (82 km) southeast. It is the largest city in Texas and was the fourth largest U.S. city when the photo was taken. Built on a flat Gulf Coastal Plain, the city is named for Sam Houston, the first president elect of the Republic of Texas. Near Clear Lake, some 22 miles from the city's downtown area, is the NASA Lyndon B. Johnson Space Center (1961), which is the command post for the flights by U.S. astronauts.